I have a Colt Walker replica, and I was wondering if I could use FFg black powder in the pistol. I'm really new to black powder so could somebody explain the difference between FFg and FFFg?
Thanks

I have a Colt Walker replica, and I was wondering if I could use FFg black powder in the pistol. I'm really new to black powder so could somebody explain the difference between FFg and FFFg?
Thanks

It's the graulation size...same chemical compound, just that the more "F's" the finer the grind. Being ground finer, has more surface area (for the same weight charge) so the finer grinds tend to burn more quickly.

(Can dig out the grain size...it's standard only for each manufacture, seems there aren't real close standards between powder makers. Basically it's a matter of passing through "X" screen size but not passing through "Y".)

Yes...can use FFg in the big Walker. Will give a bit less velocity than FFFg, but also a bit less pressure.

FFg is a little slower. Shouldn't hurt anything. More 'F's, the faster the powder.

Velocities might be a bit down, if you get any hangfires at all don't use it, or try hotter caps.

Thanks guys. I called the shop that told me that FFg was the right powder and they said since it was their mistake they would exchange it for me (even despite the fact that I had opened it for measuring powder). Makes me pretty happy with my gun shop, yet frusturated at the same time, at least they admitted their fault.
The grain size thing makes more since, what I learned in chemistry matches what you said Ribbonstone, more surface area = faster rate of reaction.

The late gun writer Elmer Keith recommended FFG black powder for cap and ball revolvers of .36 caliber or larger, and FFFG for smaller calibers.
I don't wholly agree.
I've used almost nothing but FFFG in my .36 and .44 guns with complete satisfaction. However, I have also used FFG in my .36 and .44 cap and ball revolvers on occasion and it works fine.
I don't know how velocity compared, I wasn't chronographing when I used it. Accuracy seemed to be the same between the two powders.
I've always found black powder more accurate than Pyrodex. Recently I purchased a can of 777 but haven't tried it yet. I have quite a few pounds of black powder, in FFFG and FFG granulation, so I haven't felt an urge to try the different black powder substitutes.
I once used Pyrodex quite a bit, beginning in the late 1970s, but gave up on it when it became apparent it was not as accurate as regular black powder.
I suspect that the original loads in the Colt Walker were assembled with powder akin to FFG granulation. However, I think you'll find that FFFG is cleaner burning; it is in my revolvers.
As long as you can easily obtain black powder, stick with it.

So how'd it work out?
You shoot that Walker with FFG powder yet? My bet is that it worked fine.

A long-barreled pistol like the Walker would work with FFG, I have no doubt. I have a 10" barreled .45 single-shot pistol I used FFG in for a while, with no complaints.

I tried FFG in a .45 derringer at a club 50-foot indoor range when I lived in northern Maine, and I could hear the ball rattling across the wood floor! My shooting buddy and I got a good laugh out of that (him more than me, as I recall.)